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A second important series of pyroxene minerals are the sodium-rich pyroxenes, corresponding to the 'pyroxene triangle' nomenclature. The inclusion of sodium, which has a charge of +1, into the pyroxene implies the need for a mechanism to make up the "missing" positive charge.
Jadeite is a pyroxene mineral with composition Na Al Si 2 O 6.It is hard (Mohs hardness of about 6.5 to 7.0), very tough, and dense, with a specific gravity of about 3.4.It is found in a wide range of colors, but is most often found in shades of green or white.
Hedenbergite has a number of specific properties. Its hardness is usually between five and six with two cleavage plains and conchoidal fracture. Color varies between black, greenish black, and dark brown with a resinous luster. Hedenbergite is a part of a pyroxene solid solution chain consisting of diopside and augite, and is the iron rich end ...
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Purely pyroxene-bearing volcanic rocks are rare, restricted to spinifex-textured sills, lava tubes and thick flows in the Archaean greenstone belts.Here, the pyroxenite lavas are created by in-situ crystallisation and accumulation of pyroxene at the base of a lava flow, creating the distinctive spinifex texture, but also occasionally mesocumulate and orthocumulate segregations.
Augite, also known as Augurite, is a common rock-forming pyroxene mineral with formula (Ca,Na)(Mg,Fe,Al,Ti)(Si,Al) 2 O 6. The crystals are monoclinic and prismatic. Augite has two prominent cleavages, meeting at angles near 90 degrees.
Serpentinization is a hydration and metamorphic transformation of ferromagnesian minerals, such as olivine and pyroxene, in mafic and ultramafic rock to produce serpentinite. [1] Minerals formed by serpentinization include the serpentine group minerals (antigorite, lizardite, chrysotile), brucite, talc, Ni-Fe alloys, and magnetite.
Omphacite is a member of the clinopyroxene group of silicate minerals with formula: (Ca, Na)(Mg, Fe 2+, Al)Si 2 O 6.It is a variably deep to pale green or nearly colorless variety of clinopyroxene.